An optical network consisting of multiple nodes is subject to intermittent faults that may raise alarms in the system. The invention focuses on an optical network based on the Any rate architecture. The need for an Any rate solution to seamlessly transport less common protocols within traditional telecommunication based metropolitan area network has been well established over the past decade by major carriers. On such an enclosed network that does not have any vendor mid-span meet within the network, it is possible to support a variety of native protocols. A single fault such as a client failure at a node in the network can, however, give rise to loss of client signal leading to multiple alarms detected at multiple points. A number of methods exist in the prior art for handling the loss of the client signal. One approach is to switch off the optical source. Although simple, such an approach leads to the loss of optical power and can give rise to a multitude of alarms as well as loss of Clock and Data Recovery (CDR) locks at downstream nodes in the network. Another approach is to maintain a “keep alive” signal, a fixed rate clock for example. Although optical power is maintained the CDR lock is lost and multiple alarms may be raised at downstream nodes. Examining all the raised alarms and determining the root cause alarm that leads to the solution of the actual problem that has occurred on the system is a difficult and time-consuming task. This in turn can significantly increase the time required for returning service to the network element.
Thus there is a need in the field for developing improved methods and systems for identifying client failures on an optical network that is based on the Any rate architecture.